Physics

posted by .

A uniform solid disk of radius 1.7 m and mass 81.3 kg is free to rotate on a frictionless pivot through a point on its rim.
If the disk is released from rest in the position shown by the solid circle, what is the speed of its center of mass when the disk reaches the position indicated by the dashed circle? The acceleration of gravity is 9.8 m/s^2.

The figure shows a solid circle, with a pivot point on the leftmost point of the rim. The dashed circle is basically rotated so that the pivot point is at the very top.

  • Physics -

    The center of mass goes down by the radius r

    the change in potential energy is m g r
    that is the kinetic energy
    (1/2) I w^2
    I is the moment of inertia about the pivot point which is the moment of inertia about the center + m r^2
    the velocity v = w r

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    A flat uniform circular disk (radius = 2.10 m, mass = 1.00 102 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 40.0-kg person, standing …
  2. physics

    A uniform disk with a mass of 27.3 kg and a radius of 0.309 m is free to rotate about a frictionless axle. Forces of 90.0 N and 125 N are applied to the disk, as the drawing indicates. (a) What is the net torque produced by the two …
  3. physics

    A uniform disk with a mass of 27.3 kg and a radius of 0.309 m is free to rotate about a frictionless axle. Forces of 90.0 N and 125 N are applied to the disk, as the drawing indicates. (b) What is the angular acceleration of the disk?
  4. physics 101

    A solid uniform disk of mass 21kg and radius 85cm is at rest flat on a frictionless surface. A string is wrapped around the rim of the disk and constant force of 35N is applied to the string, which does not slip on the rim, in the …
  5. physics

    A uniform disk of radius 0.48 m is mounted on a frictionless, horizontal axis. A light cord wrapped around the disk supports a 1.4 kg object, as shown. When released from rest the object falls with a downward acceleration of 3.6 m/s^2. …
  6. physics

    A disk with mass m = 8.1 kg and radius R = 0.33 m begins at rest and accelerates uniformly for t = 18 s, to a final angular speed of ω = 34 rad/s. What is the angular acceleration of the disk?
  7. physics

    A uniform circular disk of mass 24.0 g and radius 40.0 cm hangs vertically from a fixed, frictionless, horizontal hinge at a point on its circumference. A horizontal beam of electromagnetic radiation with intensity 10.0 MW/m2 is incident …
  8. Physics

    A uniform disk with mass 6 kg and radius 1.8 m is pivoted at its center about a horizontal, frictionless axle that is stationary. The disk is initially at rest, and then a constant force 31.5N is applied to the rim of the disk. The …
  9. Physics

    A uniform disk of radius 0.485 m and unknown mass is constrained to rotate about a perpendicular axis through its center. A ring with same mass as the disk\'s is attached around the disk\'s rim. A tangential force of 0.247 N applied …
  10. Physic question help

    A uniform disk with mass 9.6 kg and radius 2.7 m is pivoted at its center about a horizontal, frictionless axle that is stationary. The disk is initially at rest, and then a constant force 31.5N is applied to the rim of the disk. The …

More Similar Questions